Overfeed stoker



Nov. 2, 1937.- J. J. DURAND OVERFEED STOKER Filed July 16, 1935 5 Sheets-Sheet l x A- m H Inventor A Home! Nov. 2, 1937. J. J. DURAND OYERFEED STOKER Filed July 16, 1935 3 Sheets-Sheet 2 I IIIIIII'I/II/II/I/I Inventor flmmdzm A Home);

J. J. DURAND OVERFEED STOKER Nov. 2, 1937.

Filed July 16, 1935 5 Sheets-Sheet 3 Inventor Allorney panoa Patented Nov. 2, 19 31 rr EN T OFFICE '5 claims.

This invention relates to overfeed types of stokers.

.The primary feature of the present invention is to provide a construction that utilizes a movable pedestal for supporting the weight of the stoker and uses the pedestal as a conductor for supplying air under the grate of the furnace. Further objects of the invention areto provide fixedair supplies that control the ratio of the 10 volume of air fed under the grate to air fed over the grate in the proportion of 9 to 1; that minimizes the leakage "of air into the furnace by a design that admits tight joints; that allows withdrawal and insertion of the stoker with ease 15 and dispatch permitting easy servicing, repairing and inspection; that is strong, compact and durable; and that is comparatively inexpensive to manufacture and operate.

With the foregoing and other objects in view 20 the invention consists of a novel construction, combination and arrangement of parts as will be hereinafter more specifically described and illustrated in the accompanying drawings wherein is disclosed an embodiment of the invention, but it .is to be understood that changes, variations and modifications maybe resorted to without departing from the spirit of the claims hereunto appended.

In the drawings wherein like reference characters denote corresponding parts throughout the several views: v f

Figure '1 is a side elevation of a furnace in a dotted line skeleton view illustrating an adaptation therewith of a stoker in accordance with the 5 present invention.

Figure 2 is an enlarged fragmentary detailed vertical section through a portion of the stoker.

Figure 3 is a horizontal section taken substan-' tially on line 33 of Figure 1 and looking in the 40 direction of the arrows.

Figure 4 is a plan view of the gasket for the joint between the spout and the bowl.

Figure 5 is a fragmentary elevation through a portion of the platform with parts removed.

45 Figure 6 is a rear elevation of the assembled.

tion, ffrear is used to'indicate a direction toward the left of the drawings. 55 As is customary in installing-overfeed stokers the firebox door is removed and. in its place is substituted a plate i that. may be secured to the? furnace wall in any conventional manner. Inthis plate there is an opening ll through which extends the spout of the stoker as will hereafter appear.

It is to be understood that the features of the present invention apply to the 'overfeed type stoker wherein the coal is fed to the fire on the' grate from a point above the fire which latter 10 is indicated at l2. The stoker includes a bowl member indicated'generally at M which is made with a bottom wall l6 having-acentral opening. In the form of the invention illustrated this bowl is preferably rectangular in configuration. Rising from the bottom wall are a pair of spaced sidewalls Ilia, and an apertured front end wall Mia, and a rear end wall IS, the latter having a pair of openings a and 20b one over the other. The'top of the bowl is open, and around the open- 20 ing is a lip-I311 which receives the neck of the coal storage hopper E3. The interior of the/bowl it is divided transversely by. the horizontal wall 26 which divides the space between the side walls Hia into a coal pocket 30a and an air chamber 3|. The power driven ram 3|) reciprocates in the coal pocket and forces coal forwardly into the spout indicated generally at 20.

Secured to the rear flange Nb of the bottom wall E6 of the bowl in any suitable manner as by bolts i6cis a rearwardly extending horizontal platform I5; On the platform'is mounted a fan casing H housing a power driven fan (not shown) which casing has a neck extending through the lower opening 20am the rear wall 19 of the bowl.

The fan supplies air under predetermined pressures to the chamber 3|. The power driven ram 1 30 extends through the upper opening 20b. The ram and fan are driven by suitable transmission mechanism obvious to skilled persons from an 40 electric motor (not shown) and the platform l5 furnishes a support for the transmission mecha- .nism and motor. On the platform to the rear thereof is mountedthe electrical control box l8. which houses the customary electrical control switch for operating the parts of the stoker.

The spout 20 is an elongated hollow member oval in cross section and is made in upper and lower companion sections 2| and 22 which when coupled together form a coal chute 2 la. in the upper part and an air passage 32 in the lowenp'art which latter discharges air at the forward end through openings 33 overthe grate 5. The lower section 22 has atop wall 21' which divides the interior of the spout and aligns with wall 26 ta chute by which coal from the: hopper I3 is intermittently forced through the chute 2|a into the fire box 6 of the furnace through opening 34 in the forward end of the upper section 2|.

The spout 20 is mounted on. the bowl and supported thereby to extend forwardly in a horizontal position. For. this purpose there is a ring flange 23 on the rear end of upper section 2| bolted to the forward wall |9a of the bowl and this ring flange extends about the opening in the forward wall. The lower section 22 has a semicircular flange 24 bolted against the lower segment of the ring flange 23. Between the flange 23 and the wall |9a is heldjan asbestosgasket 25 havingan orifice 25a of fixed area therein which forms a communication between the air cham.- ber 3| and the passage 32 below the walls 26 and Air from the fan casing is transmitted through the orifice 250. into the passage 32 and is fed over the grate 5. There is also a gasket 2512 between the flange 23 and the flange 24. The

gaskets 25 and 25b form an air tight joint be- I tween the sections of the spout 20 and the bowl l4. The amount of air passing through the passage 32 is controlled by the size of the orifice 25a which is designed to admit one part air to pass over the grate to five parts of air fed under the grate. The spout 28 extendsthrough the opening II in plate In that has been. substituted for the door of the furnace. The spout may be moved into and out of the firebox of the furnace with ease and dispatch so as to permit inspection and repairs by reason of the air seal flange 35 embracing the spout. This flange is formed in two companion sections 35a and 3512, the one section 3512 having an extension lug 350 at each end over lapping the ends of the companion section 35a as will be-understood from Figure 6 of the drawings. The sections are secured in embracing relation about the spout 20 by means of a." bolt 35, the shank of which extends through openings in upper section 2| bridging the chute above the partition wall 21 so as not to interfere with the arm '13 there is a sleeve. bearing 15 which is rotatably mounted on a sleeve 38. The interior of the sleeve communicates with air chamber 3| through the bottom wall l6 of the bowl casting M. The sleeve 38 forms a part of pedestal B.

The mobile pedestal B further includes the vertical under-air conductor pipe 43 having the upper end extending through sleeve 38 and communicating with air chamber 3|. On an intermediate portion of the air conductor pipe 43 is a collar 44 having an outset annular shoulder (L on its upper end. To make an air tight seal there is a sleeve shim 46 disposed between sleeve 38 and conductor pipe 43. The lower ends of the shim 46 and sleeve 38 seat in the pocket of the outset shoulder 44a and the lower end of bearing sleeve 15 bears on the upper end of said shoulder 44a. Set screws 45 anchor the collar to the conductor 43 .and set screws 45a, anchor the outset shoulder 44a to the sleeve 38.

The mobile pedestal B further includes at its bottom an elbow casting formed with a tubular vertical leg 39 and a tubular horizontal leg 48 i and the wall of the horizontal leg 48 about the progress of the coal through the chute. About the coal in the hopper laterally of the standard or support C on which the stoker swings into and out of operative relation with the furnace. I

still retain the standard or support C upon which the parts swing but I design a pedestal B to be located beneaththe weight of the parts, utilize this pedestal for conveying the air supply to the ashpit of the furnace and place a caster wheel on the bottom of the pedestal; to impart more efliare designed to carry.

' pipe .11.

mouth of the open outer end thereof is flared as at 4|. The upper end of the vertical leg 39 of the elbowhas a. counter-bore 42 in which the lower end of the conductor pipe 43 is seated. The arrangement of the elbow and conductor pipe 43 forms a passage 41 which communicates at its upper end with chamber 3| and a part of the air from the fan casing |1 passes downwardly while the remaining portion passes forwardly through the air passage 32. The size of the passage 41 with respect to orifice 25a forming the entrance to chamber 32 is such that the volume of air passing under the furnace grate is in the proportion of nine to one of the volume of air passing into the furnace over the grate.

For conducting the air under the grate from passage 41 into the ash pit 1 of the furnace there is a flexible metallic pipe 11 having fixed by means of rivets or the like to one end thereof a tapering bushing 48 that seats in the tapered mouth 4|. On the ashpit door 9 is secured a flanged collar 49 having a tapered bore internally thereof which meshes'wlth a like tapering opening 50 in the door 9. The tapered bore in the flange collar and the opening 50 form a continuous seat for. a tapering bushing 5| 'slidably yet snugly fittingjon an outer portion of the flexible Embracing the intermediate portion of the flexible pipe 11 is a coil spring 52 one end of which maintains the movable bushing 5|- in seated relation in thebore of the collar and opening 50 while the other end of the spring bears against the bushing 48. The latter construction forms an air tight seal between the elbowand' the ashpit of the furnace for conducting air from the passage 41 in the pedestal B into the cient mobility to the stoker all of which pro- 'motes a balanced distribution of weight inmy a spindle 12 which terminates below the bowl casting I4. A horizontal laterally extending arm 13 has a sleeve 14 on its inner end rotatably ashpit of the furnace. So that the pedestal may be moved with ease and dispatch for assembling and removingth'e stoker from the furnace there.

' is bolted as at 53 a plate 54 to which is swivelled' mounted on the spindle 12 and this arm in certain types of stokers carries all of the weight of the parts of the stokers which weight is distributed laterallyof the spindle 12. On the outer end of a caster wheel 56. The caster .wheel rides on a segmental-shaped track 51 and this tracli is imbedded in the floor 58. By reason of this construction the pedestal may be moved freely about standard C while it is supporting substantially the entire weight of the stoker which movement allows the spout 2|! to be withdrawn from the firebox and permits the gland 5| and the flexible conductor pipe "to be withdrawn from the door 8 to allow repairs and inspection to the furnace. When in operating position, additional support is supplied to the stoker by means of a swinging leg formed of two aligned sections 59 and 60;

The upper end of leg section 50 is pivoted on a pin 62 which is secured to depending portions of a pair of spaced plates 18 bolted as at 19 to the opposite sides of the platform |5.. The lower end of leg section 59 has a foot piece 53 that is adapted to engage with the floor 58. The confronting ends of the leg sections are connected together by a turn buckle sleeve 6|. When it is desired to move the stoker away from the furnace, turn buckle sleeve 6| may be rotated so as to withdraw leg section 59 from the floor and permit it to be swung into dotted line position shown in Figure 1 of the drawings. When the stoker is assembled, however, the angle indicated by the arrows at 65 should be slightly greater than a right angle so that the weight of a stoker is urged forwardly making atight fit between the plate In and-the flange 35 on the spout 20.

So as to provide additional bracing for the stoker there is a metal strap brace 66 having one end secured as at 61 to a side wall of the bowl M and the rear end secured as at 68 to the control box. There is one brace 66 on each side of the stoker. Having thus described the invention, what is claimed as new is:

1. The combination with a furnace including a fire box provided with a grate, of a stoker including a bowl having an air chamber and a coal pocket, a spout secured to the bowl and extending into the fire box above the grate, said spout having a coal chute registering with the coal pocket and a conductor registering with the air chamber at one end and with the fire box at the other end to feed air over the grate, a hollow pedestal arranged to support the stoker and equipped with a passage communicating with said air chamber, a flexible air conductor communicating at one end with the passage in the pedestal and at the other end with the furnace under the grate, and bushing fittings between the ends of the flexible conductor and the pedestal and the furnace respectively.

2. The combination with a furnace including a fire box provided with a grate, of a stoker including a bowl having an air chamber and a coal pocket, a spout secured to the bowl and extend ing into the fire box above the grate, said spout having a coal chute registering with the coal pocket and a. conductor registering with the air chamber at one end and with the fire box at the other end to feed air over the grate, a-hollow pedestal arranged to support the stoker and equipped with a passage 5 communicating with said air chamber, a flexible air conductor communicating at one end with the passage in the pedestal and at the other end with the furnace under the grate and bushing fittings between the ends of the flexible conductor and the pedestaland the furnace respectively, and spring means embracing the flexible conductor for urging one of the fittings into connection with the furnace under pressure.

3. The combination with a furnace including a fire box provided with a grate, of a stoker including a bowl having an air chamber and a coal pocket, a spout secured to the bowl and extending into the fire box above the grate, said spout having a coal chute registering with the coal pocket and a conductor registering with the air chamber at one end and with the fire box at the other end to feed air over the grate, a hollow pedestal ,arranged to support the stoker and equipped with a passage communicating with said air chamber, a flexible air conductor communicating at one end with the passage in the pedestal and at the other end with the furnace under the grate, and bushing fittings between the ends of the flexible conductor and the pedestal and the furnace respectively, spring means embracing the flexible conductor for urging one of the fittings into connection with the furnace under pressure, and said pedestal being swingable.

4. The combination with a furnace including a fire box provided with a grate, of a stoker including a bowl having an air chamber and a coal pocket, a spout secured to the bowl and extending into the fire box above the grate, said spout hav-' ing a coal chute registering with the coal pocket and a conductor registering with the air chamber at one end and with the fire box at the other end to feed air over the grate, a hollow pedestal arranged to support the stoker and equipped with a passage communicating with said air chamber, a

flexible air conductor communicating at one end with'the passage in the pedestal and at the other end with the furnace under the grate, bushing fittings between the ends of the flexible conduc-- tor and the pedestal and the furnace respectively, spring means embracing the flexible conductor for urging one of the fittings into connection with the furnace under pressure, said pedestal being swingable, and an adjustable auxiliary leg swingably connected at its upperend to the stoker and adapted for engaging the floor at its lower end.

5. In an overfeed stoker, the combination of a bowl comprising a coal receiving chamber and an air chamber, a pedestal on which said bowl is mounted, a hopper mounted on thebowlin communication with said coal receiving chamber, a platform extending rearward from the bowl, a power driven fan carried by the platform and arranged to deliver air to said air chamber, a power driven coal feeding ram extending into said coal receiving chamber, a spout extending forwardly from the bowl, including a chute communicating with said coal receiving chamber and an air passage communicating with said air chamber, said chute communicate with a furnace beneath a grate therein.

JOSEPH J. DURAND. 

